Supercharger control



March 11, 1947. HQLLEY, JR 2,417,363

gurmcnmena CONTROL Filed A i-il 17, 1944 INVENFOR.

',and vice versa.

Patented Mar. 11, 1947 SUPERCHARGER CONTROL George M. Holley, J12,Grosse Pointe, Mich, assignor to George M. Holley and Earl HolleyApplication April 17, 1944, Serial No. 531,479

1 The object of this invention is to control an exhaust-driven turbosupercharger for an airplane engine. It has been common practice formany years to regulate the pressure generated by an exhaust turbosupercharger so that the absolute pressure delivered by the superchargeris a constant value regardless of altitude. It is desirable to regulatethis pressure with reference to atmospheric pressure because the engineshould develop its maximum power at sea level and power should slightlydiminish at altitude because obviously maximum power is needed ing offat sea level.

The figure shows diagrammatically the elements of my invention.

In the figure, lllis a manually controlled throttle lever connected bythe link H to the throttle lever i2 controlling a throttle l3. Airenters at M, is compressed by the supercharger I5, is discharged throughan intercooler l6, and is delivered to the carburetor ii in which islocated the throttle l3. The air is then discharged into the manifoldl8, and so to the engine cylinders 9. The xhaust escapes from the enginethrough the pipe 20 and out'through the exhaust pipe 2|. The exhaustleaving pipe 20 can take two paths, one past a throttle 22, or the otherpast the exhaust turbine 23. Obviously, when the valve 22 is closed, themaximum supercharging takes, place.

The throttle valve 22 is contrblled by the lever 24, which is connectedto the servomotor A, which is controlled by the manually controlledsupercharger regulating lever 25. -Lever 25 engages with the link 26,which engages with lever 21, which engages with a button 28, whichcompresses the spring 29 imposing a load oh diaphragm 30. Diaphragmchamber 3|v is connected through pipe 32' with annular chamber 33 intowhich th supercharger delivers air. The pipe 32 thus imposes thesupercharger pressure on the diaphragm 30. The valve 34 is an extensionof the rod 35 and acts as a servomotor valve. The rod 35 also engageswith the diaphragm 30. Thus, the valve 34 controls the servomotor piston31. Oil under pressure is delivered through the pipe 38. This pressureis applied to either the left or right hand side of piston 31 dependingon the movement of the valve 34 to the left or the right side. When therod 35 moves to the left, then the piston 31 moves to the left 011pressure escapes through pipe 39. The oil pressur admitted through thepipe 38 is also conveyed through a passage 40 to engage with a smallpiston 4| which locks when takmatically.

button 28 ,to rod 35 when the oil pressure in passage 40 is zero so thaton the failure of the oil supply or before the oil pressure is built up,the lever 25 has control over the mechanism. Another small piston 42 isalso unseated as soon as oil pressure is available in pipe 38. v

A piston 43 is connected through a yoke 44 to a lever. 45, which engageswith the roller 46, which engages a roller 47, which acts as the fulcrumof the lever 21. A fiat spring 48. applies pressure through thisfulcrum47 through the roller,

engaging the cam surface of the lever 45. The lever 45 has a fulcrum '43and is connected through a rod 50 to the yoke 44 of the piston 53. Aservomotor valve 5| supplied with oil under pressure through the pipe 52provides the motive force for the piston 43. Oil under pressure escapesthrough a pipe 54. An evacuated or partially evacuated barometricelement 53 moves the valve 5| and thus the piston 43 which moves the cam45. The restrictions 55 and 56 are provided to make th mechanismoperate. The spring 51 pushes the piston 43 to the left so that when theoil pressure fails, the lever 45 is rotated anti-clockwise and allowsthe fulcrum 41' of the lever 21 to move to the left, which reduces thepressure on the spring 29. When the oil pressure fails, a third smallpiston 58 is pushed into a locking engagement with rod 50. Oil underpressure from line 52 unlocks this small piston 53 so that wheneveroilpressure is available, the mechanism will function auto- OperationAssume that oil pressure is available and that the three lockingpistons, 42 and 58 are free,-

then if the engine is running, pipe 32 delivers supercharger pressure tothe chamber 3|, the exhaust flowing along pipe 20 rotates the turbine 23and thus operates the supercharger l5. If the pressure in 3i is not highenough to balance the combined force of the atmospheric pressure and ofthe spring 29, then the throttle 22 is closed until such time as thesupercharger l5 generates sufficient pressure to bring the servomotorvalve 34 back into the neutral position in which it is shown.

When the altitude varies, the barometric element 53 expands andcontracts. The valve 5| moves to the left and right and as it moves, somoves the piston 43, which regulates the fulcrum 41, which determinesthe spring pressure 29 so that the degree of supercharg determined by inatmospheric pressure. Hence, any desired relationship between altitudeand the boost pressure measured above the-atmospheric pressure (=gagePressure) can be maintained. For example: as the plane ascends into theair, the de-' gree of supercharge (relative to the atmospheric pressure)can be arranged to increase. However, relative to zero pressure, thedegree of supercharge may at the same time decrease slightly so that thepower will not increase with altitude.

' If the superchargewas held at a constant pressure (absolute), thepower would increase with altitude, which is an undesirablecharacteristic of constant boost pressure devices now in general use.

What I claim is:

1. A turbo supercharger control for an internal combustion engine,comprising an exhaust outlet from said engine, a turbine therein, asupercharger driven by said turbine, another exhaust outlet, an exhaustvalve therein; means responsive to the pressure above the atmospheregenerated by said exhaust driven supercharger for causing said valve toopen when a preselected supercharger pressure is exceeded. and to closewhen the supercharger pressure is below the preselected pressure, manualand barometeric means adapted to jointly select said pressure above theatmosphere.

2. A device as set forth in claim 1, inwhich the means responsive to thepressure'for causing said exhaust valve to open and close includes aservomotor.

3. A device as set forth in claim 1 in which the barometric meansadapted to select the pressure above the atmosphere generated by saidsupercharger includes a servomotor.

4. Adevice as set forth in claim 1 in which the means responsive to thepressurefor causing said exhaust valve to open and-close includes aservomotor,and in which the-barometric means adapted to selectthepressure above the atmosphere, generated by said supercharger includes aservomotor.

5. A turbo supercharger control for an internal combustion enginecomprising an exhaust outlet from said engine, a turbine therein, asuper- 4 charger driven by said turbine, another exhaust outlet, anexhaust valve therein, control means for said exhaust valve comprisingan air chamber, a moving wall therein, a pipe connecting said chamberwith the outlet from said supercharger, spring means for opposing thepressure exerted by said supercharger pressure on said wall, a lever,one portion of which is adapted to engage with said spring, barometericmeans adapted to engage with another portion of said lever, manual meansadapted to'engage with said lever at a third point whereby the load onsaid spring is jointly controlled by said manual means and by saidbarometric means.

6. A device as set forth in claim 5 in which the control means for saidexhaust valve comprising a servomotor and in which the barometric meansengaging with said lever also includes a servomotor.

- 7. A control for an internal combustion engine having an exhaustdriven turbo supercharger, an exhaust valve controlling the turbosupercharger, a controlling means responsive to the pressure produced bythe supercharger relative to atmospheric pressure for opening andclosing said valve so as to regulate the flow of exhaust gases to saidturbo supercharger, manually operated means adapted to select saidpressure, barometric means also adapted to select said pressure, saidbarometric means being adapted to control the exhaust valve jointly withthe manually oper at'ed means whereby the pressure is controlled jointlyby the manual means and by the barometric means.

GEORGE M. HOLLEY, Ja.

' REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,346,563 Sherbondy July/13, 19201,508,707 Moss Sept. 16, 1924 2,024,202 Berger Dec. 17,- 1935 2,187,737Gregory Jan. 23, 1940 r

